The Arizona abortion law barring doctors from terminating pregnancies after 20 weeks was to take effect Thursday. The judges, from the Ninth US Circuit, granted an emergency injunction blocking the law.

Activists hold a "Stand Up for Women's Health" rally in supporting preventive health care and family planning services, including abortion, in Washington in this 2011 file photo. A federal appeals court on Wednesday temporarily blocked enforcement of a tough new Arizona abortion law that bars doctors from routinely terminating a pregnancy after 20 weeks.

“We are relieved that the court blocked this dangerous ban and that women in Arizona will continue to be able to get safe, appropriate medical care,” Alexa Kolbi-Molinas, staff attorney with the ACLU Reproductive Freedom Project, said in a statement.

The statute, signed on April 12 and known as SB 2036, reduces by three to four weeks the amount of time a woman would have to decide on whether to end her pregnancy or carry the child to term. It allows doctors to perform an abortion after 20 weeks, but only in cases of “medical emergency.”

Arizona is among 10 states that have enacted laws seeking to regulate the provision of abortions during the time in a pregnancy when the fetus is unable to survive on its own outside the womb.

Doctors consider the point of fetal viability to arrive 23 or 24 weeks into a pregnancy.

A group of physicians in Arizona asked a federal judge to block the law and rule that it violates a woman’s right to decide whether to have an abortion.

On Monday, US District Judge James Teilborg found that the state law was a permissible regulation of abortion and did not violate constitutional protections.

In her motion to the court, Janet Crepps, a lawyer with the Center for Reproductive Rights, said her clients perform more than 50 pre-viability abortions at or after 20 weeks of pregnancy per year.

They were “very likely to have such a patient within the next several days and almost certain to have such a patient within the next 21 days,” she wrote.

Lawyers for Arizona had urged the Ninth Circuit panel to reject the appeal, saying the lawsuit was an impermissible challenge to an abortion regulation under the terms of a 2007 US Supreme Court precedent.

Douglas Irish, deputy county attorney in Maricopa County, said in his brief that any challenge to the Arizona law must be made on behalf of a pregnant woman seeking an abortion at or beyond the law’s 20-week limit.

Irish said Supreme Court precedent has shifted since a key ruling in 2007 when the high court approved a ban on so-called partial-birth abortions regardless of when they were performed during a pregnancy.

Arizona lawyers argue that the 2007 decision opens the door to state regulations extending into the pre-viability period of a pregnancy.

The judges ordered both parties to file appellate briefs in September and October. The order said the case would be expedited.